Trump Plaza, which cost $210 million to build in the early 1980s, sold for less than one-tenth that amount Wednesday.

ATLANTIC CITY, N.J. — Trump Plaza, the Boardwalk centerpiece of Donald Trump’s one-time Atlantic City empire, was sold Thursday to a California company for $20 million in the cheapest of a series of bargain-basement deals for distressed gambling halls in the struggling New Jersey seaside resort.

The Meruelo Group of Downey, Calif., plans to close the deal by May 31. It is the lowest price ever paid for a casino in Atlantic City.

It was not immediately clear what the new casino would be called.

The Meruelo Group, which counts construction, engineering, real estate, food service and private equity among its businesses, also owns the Grand Sierra Resort and casino in Reno, Nev.

“Trump Plaza is one of the world’s most recognized gaming resort destinations and is an integral part of the Atlantic City landscape,” said Alex Meruelo, founder and CEO of the Meruelo Group.

“Our company is thrilled to have the opportunity to become the new owners of this property, and we are firmly committed toward establishing it as one of the elite destinations in Atlantic City and on the East Coast.”

Robert Griffin, CEO of Trump Entertainment Resorts, said the deal shows the Atlantic City market is still attractive to investors, given the right price.

“This is good news for the city, for the state, and for the Plaza,” he said. “There is still considerable interest in this market.”

Trump Plaza has about 900 employees.

Trump Plaza, which cost $210 million to build, opened in May 1984 as one of Donald Trump’s pet projects. The real estate mogul has since limited his dealings in Atlantic City.

The sale leaves the company he once ran, Trump Entertainment Resorts, with just one casino, the Trump Taj Mahal Casino Resort.

Griffin also said his company would consider selling the Trump Taj Mahal, if the price were right. He said there have been no talks with potential buyers for the Taj thus far. The company sold the former Trump Marina to a Texas company that rebranded it as the new Golden Nugget in 2011.

“If someone comes in and makes an offer that makes sense, our board has shown that we are willing to do the right thing for our shareholders,” Griffin said. “Blow me away with an offer, and I’ll be happy to take it to the board.”

Trump Entertainment Resorts plans to use proceeds from the Plaza sale to pay down its debt, which will be about $270 million after the sale, Griffin said.

Trump Plaza is one of the first casinos many visitors to Atlantic City see. It sits at the foot of the Atlantic City Expressway on the Boardwalk, directly next to Boardwalk Hall, and sometimes markets itself as being in “the center of it all.”

It stands 39 stories over the Boardwalk, and has 906 hotel rooms, ranking it among the smallest of the city’s 12 casinos, the most successful of which have 2,000 or more rooms apiece.

Trump Plaza has struggled mightily in recent years, despite its central location. It has become the worst-performing casino in town in terms of casino revenue. Last month, Trump Plaza took in less than $4.9 million, a decline of more than 40 percent from a year ago.

For all of last year, Trump Plaza won just over $102 million from gamblers — or about what the city’s top casino, the Borgata Hotel Casino & Spa, wins in a good two months. Trump Plaza’s winnings for 2012 were down 25 percent from 2011.

For the third quarter of last year, the most recent period for which statistics are available, Trump Plaza had a $2.35 million gross operating profit, down nearly 34 percent from the same period in 2011.

The sale price was also consistent with the fire-sale prices casinos have been going for lately in Atlantic City. Resorts Casino Hotel sold for $31.5 million in Dec. 2010. Trump Marina Hotel Casino fetched $38 million when it was sold in May 2011 and became the Golden Nugget.

Billionaire Carl Icahn bought the Tropicana Casino and resort out of bankruptcy court for $200 million worth of deeply discounted debt; the casino originally went on the market for about $1 billion when its former owners lost their casino license.

And The Atlantic City Club Casino Hotel is being bought by the parent company of the PokerStars website site for an as-yet undisclosed sum, which is expected to be a fraction of the $513 million its owners paid for it in 2005.